System of communication



W. W MACFARLANE.

SYSTEM OF COMMUNICATION.

APPLICATION FILED MAY 15. I919.

1,370,338. Patented Mar. 1, 1921.

ATTORNEY WILLIAM W. MAGFABLAJIE, 0F ELKINS FAB/K, EPENNSYLVANIA.

SYSTEM. 015 COMMUNICATIOE.

Specification of Letters Patent,

Patented Ella/r. 1, 1923.

Application filed Hay 15, 1819. Serial No. 297,371.

To aZZ whom 2'1? may 0071067 71,.

Be it known that l, lVILLIAa-r W. lviiic- FARLANE, a citizen of the United States, and a resident of Elkins Park, county of Montgomery, and State of Pennsylvania. have invented a certain new and useful System of Communication, of which the following is a specification.

The present invention relates generally to electric systems of communication and has for its main object to lessen the expense of installation of telephone and to transmit messages with audio frequency instead of radio frequency in wireless or semiwireless apparatus.

In the accompanying drawing the invention is shown in a concrete and preferred form.

Each station is equipped with a local circuit 1 including a transmitter 32, a battery 3 and the primary winding at of a transformer. 5 is a secondary winding, the secondary windings of two stations being connected at one side only by a line conductor 6. 7 and 8 are helices constituting an intermediate winding and consisting of a copper strip say ,016 x .5 wound on separate cores 9 and 10 and in series with each other, there being'say twenty convolutions in each helix arranged in a singlelayer. Cores 9 and 10 are say in diameter, and core 9 supports helix 7 and winding 1, while core 10 supports helix 8 and winding 5.

lVinding preferably consists thirty five hundred turns of No. 28 wire, and win ing is preferably composed of one hundred and fifty thousand turns of X0 wire. All the proportions given are by way of er:- planation and are not intended limitation.

Receiver ll has one terminal 12 connected to circuit 1 and the other terminal tending at the outside of said receiver, and

, also in this form of the invention a conduccircuit with the ary coil 5 of the first station as indicated by the clotted lines and arrows.

This (lGVICB will operate when blind ends of secondaries 5 are grounded and when terminals 13 are grounded. It has, however, been found possible to transmit mes sages when there is no ground as when the operator stands on a plate of glass and when blind ends or. 5 are not grounded.

By the means described messages are ing: a plurality of sending and receiving stat-ions, each station including a local cir:

cuit having a primary Winding in series are therewith, a secondary'winding in inductive relation to the primary Winding, and an in termediate winding in inductive relation to the primary and secondary windings, aline conductor connecting one side only of the two secondary windings, and a conductor extending around the several windings iron: the local circuit to the line conductor.

3, system. of communication comprising: a plurality of sending and receiving stations, each station including a local circuit having a primary Winding in series therewith, a secondary winding-in inductive relation to the primary winding, a line conductor connecting one side only of the two secondary windings, a conductor extending around the several windings from the local circuit to the line conductor, a transmitter having both sides connected with the local circuit, and a receiver hav;

ing one side only connected to the local circuit.

4. A. system of communication comprising: a plurality of sending and receiving stations, each station including a local circult having a primary winding in series therewith, a secondary winding in inductive relation to the primary winding, and an intermediate winding in inductive relation to the primary and secondary windings, a line conductor connecting one side only of the two secondary windings, and a conductor extending around the several windings from the local circuit'to the line conductor, a

transmitter having both sides connected with the local circuit, and a receiver having 10 one side only connected to the local circuit.

Signed at Philadelphia, in the county of Philadelphia and State of Pennsylvania this 9th day of May, 1919.

WILLIAM W. MACFARLANE. 

